1. Field of the Invention
The present invention relates to a pressure detecting apparatus constituted by integrating a pressure sensor having a built-in semiconductor pressure-detecting device provided with a gauge resistance and a solenoid valve for controlling a channel of a measurement fluid into one body.
2. Description of the Related Art
FIG. 6 is a block diagram showing a conventional pressure detecting apparatus.
In FIG. 6, a pressure sensor 100 is set so that a semiconductor pressure-detecting device partitions the inside of a sensor vessel 101 into a reference pressure chamber and a measurement fluid introduction chamber. Moreover, a nipple 102 for introducing a measurement fluid into the measurement fluid introduction chamber is provided for the sensor vessel 101.
The pressure sensor 100 is set to a bracket 106 together with a solenoid valve 103. Moreover, the nipple 102 and an outlet 105 of the solenoid valve 103 are connected each other by a hose 107.
The conventional pressure detecting apparatus thus constituted is set to, for example, the chassis in an engine room and used by connecting a hose from an engine intake pipe to an inlet 104 of the solenoid valve 103.
Moreover, intake air introduced from the engine intake pipe through the hose is introduced into the measurement fluid introduction chamber through the inlet 104, outlet 105, hose 107, and nipple 102 when the solenoid valve 103 opens. Therefore, in the pressure sensor 100, the semiconductor pressure-detecting device is distorted due to the differential pressure between the reference pressure chamber and the measurement fluid introduction chamber and the pressure of the intake air is detected.
As described above, the conventional pressure detecting apparatus requires the bracket 106 and the hose 107 in order to integrate the pressure sensor 100 and the solenoid valve 103 into one body because the pressure sensor 100 and the solenoid valve 103 are separate products. Thus, problems occur that a unit is increased in size and a large setting space is necessary.
Moreover, because the pressure sensor 100 and the solenoid valve 103 are respectively provided with a connector for electrical connection, problems occur that two pairs of connectors are also necessary for the chassis harness side and the connecting operation becomes troublesome.